T3 Cast Rear Wheel - strange bearing failure.

[Wandhoop]

I have a 1980 T3 with cast wheels - I suspect from a slightly later 1000 SP. All has been fine until an intermittent grinding noise from the rear wheel. At first I thought it was a stuck brake caliper catching on the disc but it wasn't that. Closer inspection with the caliper removed I found that the wheel only turned freely for perhaps half a turn before 'binding'. In the position where it could freely turn the wheel could be rocked side to side, suggesting a loose bearing.

I removed the wheel and found that the bearing on the right hand side (drive side) is loose in its housing. See picture.


The outer race of the bearing 'rocks' in the wheel (which is what I could feel when the wheel was on the bike). The Flexible Coupling Disk (GU14335203) or "Drive Plate" - the part that has the splines on the other side that fits into the cush drive rubbers - is locked solid onto the wheel. I would have expected to be able to slide it off? Looking at the parts list I think there is a 'hub' (GU14632250) that the drive plate slides over? Number 14 in this picture.



I'd then expect the wheel bearing itself to fit into this hub? That way the wheel is turning on the axle via the hub and the drive from the engine is via the drive plate and cush rubbers. Can anyone confirm if my understanding is correct?

Looking closer at the wheel bearing (picture below) it appears that some of the hub has broken away which is why the bearing is not fully supported and thus moves about.


To the bottom-right you can see metal between the bearing outer race and the drive plate splines but around the top this is missing - what metal you can see is further below the upper edge of the bearing.

I'm reasonably competent maintaining my own bikes (have Brits and previous Italian) *but* I really don't want to damage anything further nor buy any parts that I don't need (they're all expensive!) without getting advice from folks that have perhaps had one of these wheels apart before.
My questions in summary are:
1. Does the wheel bearing mount in the hub?
2. How does the hub fit into the rest of the wheel? Is it a 'fit once' or can it be replaced? If it is the root cause of my problem is the whole wheel basically scrap?
3. Should the drive plate 'just' lift off the hub?
4. Am I getting this completely wrong?

I'm in England, UK if anyone wants to recommend suppliers, etc.

Thanks in advance!

Miles

 

[john zibell]

It looks like you have a California II rear wheel. The darn parts illustration doesn't show the side you need to see. It looks like you have removed the retaining ring so a little muscle is needed to get that drive plate out. I think you will need another drive plate and do replace both bearings. Bearing have numbers on them and you can get them at any bearing supply house. The drive plate is a Guzzi only part and is part number 14335203, or updated number GU30335260. They appear to still be in production so a local dealer can get one for you.

 

[Amboman]

The photo shows an SP wheel, the illustration shows a Cal II wheel.

1. Yes.
2. It is a tight press fit into the cast wheel and has a circlip on the brake disk side.
3. If the drive plate won't budge, one can remove the brake disc and use the brake disk bolts to push the drive plate out. It does look like some of your central hub has broken away.
4. No.

The part number of the hub is: 14632250


After a brief search, I'm not finding anyone with it in stock.

 

[john zibell]

Charlie, thanks for the clarification. It turns out the drive plate I found doesn't have the hub included. Looks like his only option is to find a used drive plate. The good think is they were used for many years without change. Even Harper's shows the hub as a pre-order.

 

[Amboman]

Charlie, thanks for the clarification. It turns out the drive plate I found doesn't have the hub included. Looks like his only option is to find a used drive plate. The good think is they were used for many years without change. Even Harper's shows the hub as a pre-order.

It's the hub that appears to be damaged, not the drive plate. Maybe it will be more clear once the drive plate is removed.

 

[john zibell]

It's the hub that appears to be damaged, not the drive plate. Maybe it will be more clear once the drive plate is removed.

I think his best option is to find a used drive plate with a good hub and swap out the assembly. Then install new bearings on both sides.

 

[Amboman]

The hub is a completely separate piece from the drive plate - it's not part of the drive plate and does not come with the drive plate.

Hub:



Drive plate:

 

[john zibell]

But a used drive plate will have the hub in it. Whenever I've taken off a drive plate, the hub came out with it.

 

[Amboman]

How would the hub come out with it? There's a circlip on the disk side keeping it from coming out, plus it's a press fit in the wheel.

 

[john zibell]

How would the hub come out with it? There's a circlip on the disk side keeping it from coming out, plus it's a press fit in the wheel.

It has been years since I pulled one on a spoke wheel (T series bike), but my memory is that it came with the drive plate. My memory may be failing, but that is what I remember.

 

[Big-Dave]

I removed the wheel and found that the bearing on the right hand side (drive side) is loose in its housing. See picture.

View attachment 36129
The outer race of the bearing 'rocks' in the wheel (which is what I could feel when the wheel was on the bike). The Flexible Coupling Disk (GU14335203) or "Drive Plate" - the part that has the splines on the other side that fits into the cush drive rubbers - is locked solid onto the wheel. I would have expected to be able to slide it off? Looking at the parts list I think there is a 'hub' (GU14632250) that the drive plate slides over? Number 14 in this picture.

View attachment 36130

I'd then expect the wheel bearing itself to fit into this hub? That way the wheel is turning on the axle via the hub and the drive from the engine is via the drive plate and cush rubbers. Can anyone confirm if my understanding is correct?

Looking closer at the wheel bearing (picture below) it appears that some of the hub has broken away which is why the bearing is not fully supported and thus moves about.
View attachment 36131

To the bottom-right you can see metal between the bearing outer race and the drive plate splines but around the top this is missing - what metal you can see is further below the upper edge of the bearing.

I'm reasonably competent maintaining my own bikes (have Brits and previous Italian) *but* I really don't want to damage anything further nor buy any parts that I don't need (they're all expensive!) without getting advice from folks that have perhaps had one of these wheels apart before.
My questions in summary are:
1. Does the wheel bearing mount in the hub?
2. How does the hub fit into the rest of the wheel? Is it a 'fit once' or can it be replaced? If it is the root cause of my problem is the whole wheel basically scrap?
3. Should the drive plate 'just' lift off the hub?
4. Am I getting this completely wrong?

I'm in England, UK if anyone wants to recommend suppliers, etc.

Thanks in advance!

Miles

Try Fowlers of Bristol. Phone them if necessary, they are quite helpful.

 

[Wandhoop]

Sorry I've been quiet for a while, been away on a (work) training course.
Have been working on the wheel with a little progress.

Amboman - thank you for identifying it as an SP wheel. That kinda makes sense from what I know of the bike's history before I got it. Your mention the circlip on the brake side - I took the brake disk off and was shocked to see no circlip!


Just held in by friction. So will definitely add that.

I tried your suggestion of using the brake disk bolts to push the drive plate off the hub but no joy. I suspect (based on the bounce) that all are aligned with cush rubbers :-(.

I decided to risk removing the bearing on the drive side and was surprised to find that the hub inner face does not appear to be damaged. Now I'm confused as to how the bearing could have worked loose, unless a previous owner had not fully seated it in the hub - but it has been fine for 8 years and many 1000's miles. I don't have any precision measuring instruments so will be taking it to an engineering shop tomorrow to get the diameter and eccentricity checked.

I still have the problem that the drive plate is stuck solid to the hub, so no effective cush drive. I've been applying penetrating oil to the hub/drive plate join every evening and bent several tire levers trying to lever the plate up (block of wood to protect the alloy, end of lever under two or three teeth on the drive plate). Any other ideas?

Big-Dave - thanks for the Fowlers tip. That confirms that the drive plate is no longer available from Guzzi and the hub is £188 and a special order from Italy.

So I really need to get the drive plate off the hub without damaging either and hope that the hub is either OK or can be shimmed to hold the bearing. I'll see if the engineering shop has any suitable puller or other ideas.



Thanks very much for your advice - any other suggestions welcome!

Miles

 

[V700Steve]

The one on my Cal2 was same as yours, I cut a slot w/die grinder from one end to other. Used a chisel on the edge to peel hub back. Got it apart from seized. It has grove to put grease on so it turns but no one pulls theirs apart to lube. I have pics here if I can find.
Nope couldn't find.

 

[john zibell]

If you have an electric heat gun, you can try to warm up the wheel where the drive plate is located. The alloy will expand more that the steel drive plate.

 

[Wandhoop]

Some good news! My local engineering shop made up a puller that spread the load across the splines and managed to pull the drive plate off. I've given the inner surface a clean up including the lubrication grooves. He removed the bearing from the hub and we were surprised to find that the hub had not actually broken up. The hub bearing seat measured 12 thou (0.3mm) oversize - which explains why the bearing was not seated correctly. But the spacers *should* have held it in place, so I need to check those. I think there may be a problem with the cush drive - see a separate topic I'll start above. I've used some Loctite retainer to take up the slack in the bearing as the hub is not thick enough to sleeve.
So, not as bad as I feared, some progress, but not sorted yet!
Thanks for your help guys, please see my other post.